Unprecedented Radiation Resistant Thorium–Binaphthol Metal–Organic Framework

A thorium–organic framework
(TOF-16) containing
hexameric secondary building units connected by functionalized binaphthol
linkers was synthesized, characterized, and irradiated to probe its
radiation resistance. Radiation stability was examined using γ-rays
and 5 MeV He2+ ions to simulate α particles. γ-irradiation
of TOF-16 to an unprecedented 4 MGy dose resulted in
no apparent bulk structural damage visible by X-ray diffraction. To
further probe radiation stability, we conducted the first He2+ ion irradiation study of a metal–organic framework (MOF).
Diffraction data indicate onset of crystallinity loss upon approximately
15 MGy of irradiation and total loss of crystallinity upon exposure
to approximately 25 MGy of He2+ ion irradiation. The high
radiation resistance observed suggests MOFs can withstand radiation
exposure at doses found in nuclear waste streams and highlights the
need for a systematic approach to understand and eventually design
frameworks with exceptional radiation resistance.